ffmpeg/libavformat/flacenc.c

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/*
* raw FLAC muxer
* Copyright (c) 2006-2009 Justin Ruggles
*
* This file is part of Libav.
*
* Libav is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* Libav is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/channel_layout.h"
#include "libavutil/opt.h"
#include "libavcodec/flac.h"
#include "avformat.h"
#include "flacenc.h"
#include "vorbiscomment.h"
#include "libavcodec/bytestream.h"
typedef struct FlacMuxerContext {
const AVClass *class;
int write_header;
/* updated streaminfo sent by the encoder at the end */
uint8_t *streaminfo;
} FlacMuxerContext;
static int flac_write_block_padding(AVIOContext *pb, unsigned int n_padding_bytes,
int last_block)
{
avio_w8(pb, last_block ? 0x81 : 0x01);
avio_wb24(pb, n_padding_bytes);
while (n_padding_bytes > 0) {
avio_w8(pb, 0);
n_padding_bytes--;
}
return 0;
}
static int flac_write_block_comment(AVIOContext *pb, AVDictionary **m,
int last_block, int bitexact)
{
const char *vendor = bitexact ? "Libav" : LIBAVFORMAT_IDENT;
unsigned int len;
uint8_t *p, *p0;
ff_metadata_conv(m, ff_vorbiscomment_metadata_conv, NULL);
len = ff_vorbiscomment_length(*m, vendor);
p0 = av_malloc(len+4);
if (!p0)
return AVERROR(ENOMEM);
p = p0;
bytestream_put_byte(&p, last_block ? 0x84 : 0x04);
bytestream_put_be24(&p, len);
ff_vorbiscomment_write(&p, m, vendor);
avio_write(pb, p0, len+4);
av_freep(&p0);
p = NULL;
return 0;
}
static int flac_write_header(struct AVFormatContext *s)
{
int ret;
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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AVCodecParameters *par = s->streams[0]->codecpar;
FlacMuxerContext *c = s->priv_data;
if (!c->write_header)
return 0;
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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ret = ff_flac_write_header(s->pb, par->extradata,
par->extradata_size, 0);
if (ret)
return ret;
/* add the channel layout tag */
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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if (par->channel_layout &&
!(par->channel_layout & ~0x3ffffULL) &&
!ff_flac_is_native_layout(par->channel_layout)) {
AVDictionaryEntry *chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK",
NULL, 0);
if (chmask) {
av_log(s, AV_LOG_WARNING, "A WAVEFORMATEXTENSIBLE_CHANNEL_MASK is "
"already present, this muxer will not overwrite it.\n");
} else {
uint8_t buf[32];
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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snprintf(buf, sizeof(buf), "0x%"PRIx64, par->channel_layout);
av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", buf, 0);
}
}
ret = flac_write_block_comment(s->pb, &s->metadata, 0,
s->flags & AVFMT_FLAG_BITEXACT);
if (ret)
return ret;
/* The command line flac encoder defaults to placing a seekpoint
* every 10s. So one might add padding to allow that later
* but there seems to be no simple way to get the duration here.
* So let's try the flac default of 8192 bytes */
flac_write_block_padding(s->pb, 8192, 1);
return ret;
}
static int flac_write_trailer(struct AVFormatContext *s)
{
AVIOContext *pb = s->pb;
int64_t file_size;
FlacMuxerContext *c = s->priv_data;
uint8_t *streaminfo = c->streaminfo ? c->streaminfo :
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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s->streams[0]->codecpar->extradata;
if (!c->write_header || !streaminfo)
return 0;
if (pb->seekable) {
/* rewrite the STREAMINFO header block data */
file_size = avio_tell(pb);
avio_seek(pb, 8, SEEK_SET);
avio_write(pb, streaminfo, FLAC_STREAMINFO_SIZE);
avio_seek(pb, file_size, SEEK_SET);
avio_flush(pb);
} else {
av_log(s, AV_LOG_WARNING, "unable to rewrite FLAC header.\n");
}
av_freep(&c->streaminfo);
return 0;
}
static int flac_write_packet(struct AVFormatContext *s, AVPacket *pkt)
{
FlacMuxerContext *c = s->priv_data;
uint8_t *streaminfo;
int streaminfo_size;
/* check for updated streaminfo */
streaminfo = av_packet_get_side_data(pkt, AV_PKT_DATA_NEW_EXTRADATA,
&streaminfo_size);
if (streaminfo && streaminfo_size == FLAC_STREAMINFO_SIZE) {
av_freep(&c->streaminfo);
c->streaminfo = av_malloc(FLAC_STREAMINFO_SIZE);
if (!c->streaminfo)
return AVERROR(ENOMEM);
memcpy(c->streaminfo, streaminfo, FLAC_STREAMINFO_SIZE);
}
if (pkt->size)
avio_write(s->pb, pkt->data, pkt->size);
return 0;
}
static const AVOption flacenc_options[] = {
{ "write_header", "Write the file header", offsetof(FlacMuxerContext, write_header), AV_OPT_TYPE_INT, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
{ NULL },
};
static const AVClass flac_muxer_class = {
.class_name = "flac muxer",
.item_name = av_default_item_name,
.option = flacenc_options,
.version = LIBAVUTIL_VERSION_INT,
};
AVOutputFormat ff_flac_muxer = {
.name = "flac",
.long_name = NULL_IF_CONFIG_SMALL("raw FLAC"),
.priv_data_size = sizeof(FlacMuxerContext),
.mime_type = "audio/x-flac",
.extensions = "flac",
.audio_codec = AV_CODEC_ID_FLAC,
.video_codec = AV_CODEC_ID_NONE,
.write_header = flac_write_header,
.write_packet = flac_write_packet,
.write_trailer = flac_write_trailer,
.flags = AVFMT_NOTIMESTAMPS,
.priv_class = &flac_muxer_class,
};